Frequency of thyroid dysfunction among rheumatoid arthritis patients at the Kenyatta National Hospital, Nairobi, Kenya

Citation:
MW N, GO O, M M, W S. "Frequency of thyroid dysfunction among rheumatoid arthritis patients at the Kenyatta National Hospital, Nairobi, Kenya." afr j Rheumatal. 2022;10(1):34-44.

Abstract:

Background: Rheumatoid Arthritis
(RA) affects 0.5-1% of the adult
population. A higher prevalence of
thyroid dysfunction is observed in
patients with RA compared to the
general population.
Objectives: To establish the
frequency of thyroid dysfunction
among ambulatory RA patients and
to describe the association between
thyroid dysfunction and the patients’
socio-demographic characteristics,
clinical characteristics, level of disease
activity, and their functional status.
Design: This was a cross-sectional
descriptive study.
Methods: Adult patients on follow
up for RA at the outpatient clinic were
sampled. Sociodemographic data was
recorded. The Clinical Disease Activity
Index (CDAI) and Health Assessment
Questionnaire (HAQ) scores were
computed from examination findings
and questionnaires respectively. A
venous blood sample was analyzed for
Thyroid-Stimulating Hormone (TSH),
free triidothyronine (fT3), and free
tetraiodothyronine (fT4). This data
was analyzed to determine frequencies
and associations.
Results: Seventy-six patients were
recruited into the study. Sixty-one
participants were female. The mean
TSH level was 5.8Miu/L. The frequency
of thyroid dysfunction was 47.4%.
Overt hypothyroidism was the most
common form of thyroid dysfunction at
39.5% while 6.6% had Sick Euthyroid.
Majority of the participants, 75%, had
low disease activity, mean CDAI was
11.6. Forty-one (53.9%) participants
had no disability, mean HAQ was
0.5. Correlations between thyroid
dysfunction and advancing age,
duration of disease, level of disease
activity, and functional disability did
not attain statistical significance.
Conclusion: Thyroid dysfunction
is common among patients with RA
with no significant association found
between thyroid dysfunction sociodemographic characteristics, clinical
characteristics, level of disease activity,
and functional status.
Key words: Thyroid dysfunction,
Rheumatoid arthritis, Disease activity,
Functional disability
Introduction
Rheumatoid Arthritis (RA) is a
symmetric polyarthritis with a variety
of systemic manifestations. In the
general population thyroid dysfunction
affects 1-10% of adults, with variations
in geographical areas, age and sex1
.
The causes of thyroid dysfunction
include; iodine deficiency, infections
and autoimmune associated thyroid
disease2
. Thyroid dysfunction is more
prevalent in patients with autoimmune
diseases such as RA. This is attributed
to overlap of autoimmune conditions
that are initiated by loss of tolerance to
self-antigens3
.
The burden of thyroid dysfunction
among RA patients has been found
to vary between 6-47% in various
studies. The entire spectrum of thyroid
dysfunction has been described,
however, hypothyroidism occurs
more frequently. Patients with thyroid
dysfunction have higher RA disease
activity scores and poorer functional
status measured using the

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